Hi My name is Ed, i have a 1985 Monte Carlo SS that has a cooling problem.  I recently swapped the old 355 small block with a early 90's 350 out of a retired police car.  The  whole motor has been revamped with rebuilt heads, beefy cam shaft and a 2,000 stall converter.  I'm running a stock fan with a clutch, and cruising temp is about 215 degrees.  Do i need dual electric fans to cool it down? It currently has a 180 degree thermostat.  Any ideas?  Thanks!  

What are you running for water pump? Did you burp all the air out of it? Where is the coolant sensor located, head or Intake? Did you put a fan shroud back on the rad? How far is the fan in to the shroud?  

http://forums.chevyhiperformance.com/70/6806087/general-chevy-discussion/gm-fast-burn-heads/index.html  

Also did you put the spring back in the bottom rad hose, They will collapse and over cause over heating  

Did you change the timing?  Big beefy cams will over heat the engine on stock timing set.  

In Forum,  a guy with a 85 Olds had put the fan on backwards pushing air instead of drawing so check that. Also might want to experiment and take out thermostat and see what effect that has. If improved, try a 160 degree.